Assay cartridges and methods of using the same

Abstract

Assay cartridges are described that have a detection chamber, preferably having integrated electrodes, and other fluidic components which may include sample chambers, waste chambers, conduits, vents, bubble traps, reagent chambers, dry reagent pill zones and the like. In certain embodiments, these cartridges are adapted to receive and analyze a sample collected on an applicator stick. Also described are kits including such cartridges and a cartridge reader configured to analyze an assay conducted using an assay cartridge.

What is claimed is: 
     
       1. An assay cartridge comprising:
 a cartridge body having a top longitudinal plane and an opposite bottom, 
 a sample introduction port located on the top longitudinal plane of the cartridge body; 
 a sample indicator window located on the top longitudinal plane of the cartridge body; 
 a sample chamber including a sample well configured to receive a liquid sample through the sample introduction port, and further configured such that a liquid surface at a liquid level of the liquid sample represents an air-liquid boundary when the sample well cannot contain any additional liquid and the liquid surface of the liquid sample is substantially parallel to the opposite bottom of the cartridge body, 
 wherein the cartridge body is configured to permit passage of light therethrough and includes an angled surface providing a reflecting surface located and disposed so as to reflect light from the liquid surface at the air-liquid boundary when the sample well cannot contain any additional liquid approximately ninety degrees to the sample indicator window, 
 wherein the reflecting surface is positioned at a non-zero angle relative to the liquid surface of the liquid sample when the sample well cannot contain any additional fluid, between the sample indicator window and the opposite bottom and on a side of the sample chamber. 
 
     
     
       2. The assay cartridge of  claim 1  wherein said sample indicator window comprises an indicating feature. 
     
     
       3. The assay cartridge of  claim 2  wherein the indicating feature is an indicating line that corresponds with reflected light from the liquid surface of the liquid sample within the sample chamber when the liquid level has a fluid level selected from the group consisting of a sample minimum, a sample maximum, a target level, and a combination thereof. 
     
     
       4. The assay cartridge of  claim 2  wherein said indicating feature is a boundary of the sample indicator window. 
     
     
       5. The assay cartridge of  claim 1  wherein said reflecting surface is a mirrored surface. 
     
     
       6. The assay cartridge of  claim 1  wherein said reflecting surface is provided by total internal reflection at the angled surface in said cartridge body. 
     
     
       7. The assay cartridge of  claim 6  wherein said angled surface is configured such that an angle of incidence of light from the liquid surface is greater than a critical angle for total internal reflection at said reflecting surface. 
     
     
       8. The assay cartridge of  claim 7 , wherein the cartridge body further includes a plurality of internal surfaces defining an internal cavity, wherein the plurality of internal surfaces includes the angled surface. 
     
     
       9. The assay cartridge of  claim 1  wherein the cartridge body further comprises a cartridge top, a cartridge bottom and a cover layer mated to the cartridge bottom, wherein the cartridge top is configured to permit passage of light therethrough and includes the top longitudinal plane, and the cover layer includes the opposite bottom. 
     
     
       10. The assay cartridge of  claim 1 , further comprising a sample overflow conduit and an overflow chamber, wherein the sample chamber is connected to the overflow chamber via the sample overflow conduit, the sample overflow conduit being configured to permit the liquid sample to flow into the overflow chamber when the liquid surface of the liquid sample reaches a top of the sample well when the liquid surface is substantially parallel to the opposite bottom. 
     
     
       11. The assay cartridge of  claim 10 , further comprising a sample vent port and a vent conduit, wherein the overflow chamber is connected to the sample vent port via the vent conduit. 
     
     
       12. The assay cartridge of  claim 11  wherein said vent conduit is positioned at or near the top of said overflow chamber. 
     
     
       13. The assay cartridge of  claim 1  wherein said sample introduction port comprises a sealable closure including a sealing/capping mechanism comprising (a) a flexible hinge; (b) a latching mechanism; and (c) a retention component comprising a retention ring or tab. 
     
     
       14. The assay cartridge of  claim 13  wherein said sealing/capping mechanism is a modular detachable insert comprising a cap for sealing said sample chamber. 
     
     
       15. The assay cartridge of  claim 1 , wherein the sample indicator window is located proximate to the sample chamber. 
     
     
       16. The assay cartridge of  claim 1 , wherein the cartridge body is configured to permit passage of light along at least a portion of the sample chamber. 
     
     
       17. An assay cartridge comprising:
 a cartridge body having a top surface, a bottom surface and at least one side connecting the top surface to the bottom surface, wherein the cartridge body is configured to permit passage of light therethrough, 
 a sample introduction port located on said top surface, 
 a sample chamber including a sample well configured to receive a liquid sample through the sample introduction port, and further configured such that a liquid surface at a liquid level of the liquid sample represents an air-liquid boundary when the sample well cannot contain any additional liquid and the liquid surface of the liquid sample is substantially parallel to the bottom surface of the cartridge body, 
 an angled surface in the cartridge body providing a reflecting surface located and disposed so as to reflect light from the liquid surface at the air-liquid boundary when the sample well cannot contain any additional liquid approximately ninety degrees to a sample indicator window, and 
 the sample indicator window also located on said top surface, 
 wherein the sample indicator window is spaced apart from the sample introduction port, and wherein the reflecting surface is located between the sample indicator window and the bottom surface and on a side of the sample chamber. 
 
     
     
       18. The assay cartridge of  claim 17 , wherein said reflecting surface is provided by total internal reflection at the angled surface in said cartridge body. 
     
     
       19. The assay cartridge of  claim 18 , wherein said angled surface is configured such that an angle of incidence of light from the liquid surface is greater than a critical angle for total internal reflection at said reflecting surface. 
     
     
       20. The assay cartridge of  claim 19 , wherein the cartridge body further includes a plurality of internal surfaces defining an internal cavity, wherein the plurality of internal surfaces includes the angled surface. 
     
     
       21. The assay cartridge of  claim 17 , further comprising a sample overflow conduit, wherein the sample chamber is connected to the sample overflow conduit, the sample overflow conduit being configured to permit the liquid sample to flow from the sample well when the liquid surface of the liquid sample reaches a top of the sample well when the liquid surface is substantially parallel to the bottom surface. 
     
     
       22. The assay cartridge of  claim 21 , further comprising an overflow chamber, wherein the sample overflow conduit is further connected to the overflow chamber. 
     
     
       23. The assay cartridge of  claim 22 , further comprising a vent, wherein the overflow chamber is connected to the vent. 
     
     
       24. The assay cartridge of  claim 17 , wherein the cartridge body includes an injection-molded top layer and an injection-molded bottom layer. 
     
     
       25. The assay cartridge of  claim 24 , wherein the cartridge body further includes a cover layer connected to the bottom layer. 
     
     
       26. The assay cartridge of  claim 17 , wherein said sample indicator window comprises an indicating feature. 
     
     
       27. The assay cartridge of  claim 26 , wherein the indicating feature is an indicating line that corresponds with reflected light from the liquid surface of the liquid sample within the sample chamber when the liquid level has a fluid level is selected from the group consisting of a sample minimum, a sample maximum, a target level, and a combination thereof.